The progression of motor vehicles, such as, for example, sport utilities and station wagons, have included a desire to make full use of available space for storage. One such example is the inclusion of additional storage compartments located in the lower surface of a sport utility vehicle or station wagon. These storage compartments are concealed by a load floor, which must provide structural integrity to support the mass of heavy objects being transported in the rear of the vehicle on top of the load floor. Alternatively, stationary load floors have been used when additional storage area is not available. The use of these load floors have proven to be expensive, heavy, and not structurally sound. Presently, removable load floors are produced from blow molding a polypropylene material, possibly glass-filled, which is extremely heavy and not structurally sound. Alternatively, glass-reinforced polyurethane has also been used. While glass-reinforced polyurethane is typically lighter than blow-molded polypropylene, it is extremely expensive and tends to flex under stress. Additionally, stationary load floors have been manufactured from these materials and have also not provided the physical properties required for use in the motor vehicles. While a tub of the storage compartment does not impede upon the carrying capacity of a rearward storage area, the amount of weight of various loads, which may be positioned on the load floor directly above the tub is limited due to the load carrying capacity of conventional covers. As a result, these various loads of significant weight cannot be placed above the tub.
Various methods and designs have been devised for manufacturing load floors and liners. These methods and designs, disclosed in the U.S. Pat. No. 4,423,900 to Sugimoto et al.; U.S. Pat. No. 5,016,934 to Pelz; U.S. Pat. No. 5,437,924 to Decker, III et al.; U.S. Pat. No. 5,836,637 to Laginess et al; U.S. Pat. No. 5,971,462 to Bell et al.; U.S. Pat. No. 6,358,599 to Deibel et al.; and the U.S. patent application No. 2001/0046587 to Michael are widely used today in the automotive industry.
The U.S. Pat. No. 5,971,462 to Bell, for example, teaches a reinforced cover or load floor for a spare tire storage system having a tub located below a floor of a vehicle. The reinforced cover is formed from blow-molded dual layers. The dual layers are preferably molded from a 30% glass filled polypropylene but can be constructed of any suitable material. The dual layers define an upper surface, which may be carpeted, and a lower surface on opposite sides of the cover. The cover includes a perimeter edge that covers an opening in the floor of a motor vehicle. The cover includes a plurality of reinforcing members that add rigidity to the cover and extend in a radial direction from the center of the cover. The reinforced cover taught by the U.S. Pat. No. 5,971,462 is too complex to manufacture and does not provide a solution to achieve a reinforced cover or a load floor having a reduced mass while maintaining structural integrity at a low cost.
The U.S. patent application No. 2001/0046587 to Michael for example, teaches a laminated structural board. The board includes a semi-rigid foam substrate as a core. Preferably, the semi-rigid foam substrate is molded from polyurethane or other foam composite. Each of the opposing sides of the semi-rigid foam substrate is coated with chopped fiberglass encapsulated between two adhesive layers. The adhesive secures the fiberglass to the semi-rigid foam substrate at the interface and provides outer adhesive layers and additional structural integrity to the semi-rigid foam substrate. Similar to the aforementioned U.S. Pat. No. 5,971,462, the laminated structural board taught by the U.S. patent application No. 2001/0046587 does not provide a solution to achieve a load floor having a reduced mass while maintaining structural integrity at a low cost.
But even with the aforementioned methods and designs, to the extent it is effective, there is always need for improvements in a load floor that is less expensive, lighter, and more structurally sound than materials presently being used in the methods and designs taught by the aforementioned patens.